Clutch control device

ABSTRACT

A clutch control device includes an ECU that controls a clutch actuator, the ECU sets a control target value of the clutch capacity according to the operation amount detected by the clutch operation amount sensor, and executes feedback control so that the control parameter which is detected by the control parameter sensor approaches the control target value, and changes a method of the feedback control when the control parameter reaches a predetermined control state change determination value during the feedback control.

CROSS-REFERENCE TO RELATED APPLICATION

Priority is claimed on Japanese Patent Application No. 2017-226776,filed Nov. 27, 2017, the content of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a clutch control device.

Description of Related Art

In the related art, a configuration in which an intervention of a manualoperation with a clutch lever during automated control of a clutch by anactuator is possible is known (for example, see Japanese UnexaminedPatent Application, First Publication No. 2014-070681).

In Japanese Unexamined Patent Application, First Publication No.2014-070681, in order to smoothly perform an intervention of a manualoperation during automated control of a clutch, in a state in which adifference between calculation results of a clutch capacity duringautomated control and a clutch capacity during a manual operation islarge, switching to a calculated value of the clutch capacity during themanual operation is prevented and abrupt variation of the clutchcapacity is avoided, and thereby, it is made possible to perform anintervention of the manual operation without causing an unease.

SUMMARY OF THE INVENTION

Incidentally, in the related art, a connection performance(responsiveness) when the clutch is reconnected after an intervention (aclutch disconnection operation) of a manual operation with a clutchlever is not mentioned.

Especially, when the actuator is feedback controlled, if same controlsare executed before and after of the clutch connection, there is a casein which the delay occurs in the clutch connection or difference fromthe control target value gets extremely large.

In addition, it is also necessary to consider a case in which friction(a flow resistance or pressure loss in an oil passage) is present in ahydraulic path of a clutch operation system.

An aspect of the present invention is directed to optimize the feedbackcontrol of an actuator in a clutch control device in which a manualoperation of the clutch can be performed via the actuator.

(1) A clutch control device according to an aspect of the presentinvention includes an engine; a gearbox; a clutch device thatdisconnects and connects a power transmission between the engine and thegearbox; a clutch actuator that drives the clutch device and changes aclutch capacity; a controller that calculates a control target value ofthe clutch capacity; a control parameter sensor that detects a controlparameter of the clutch capacity; a clutch operator that manuallyoperates the clutch device; and a clutch operation amount sensor thatconverts an operation amount of the clutch operator into an electricalsignal, wherein the controller sets a control target value of the clutchcapacity according to the operation amount detected by the clutchoperation amount sensor, executes feedback control so that the controlparameter which is detected by the control parameter sensor approachesthe control target value, and changes a method of the feedback controlwhen the control parameter reaches a predetermined control state changedetermination value during the feedback control.

(2) In the aspect of above mentioned (1), the controller may perform thefeedback control on the basis of an I term in a PID control before thecontrol parameter reaches the control state change determination value,and may perform the feedback control on the basis of a P term in the PIDcontrol after the control parameter reaches the control state changedetermination value.

(3) In the aspect of above mentioned (1) or (2), the clutch device mayswitch whether to perform the power transmission or not to perform thepower transmission when the control parameter reaches the control statechange determination value.

(4) In the aspect of any one of above mentioned (1) to (3), thecontroller may calculate a clutch operation speed on the basis of anoperation amount detected by the clutch lever operation amount sensor,and may vary the control state change determination value according tothe clutch operation speed.

(5) In the aspect of any one of above mentioned (1) to (4), the clutchcapacity may be controlled by the hydraulic pressure, a master cylinderof the clutch actuator and a slave cylinder of the clutch device may beconnected to each other via a hydraulic pressure pipeline, and thecontrol parameter sensor that is a slave hydraulic pressure sensor maybe disposed in the hydraulic pressure pipeline.

(6) In the aspect of above mentioned (5), when the hydraulic pressuredecreases the clutch capacity decreases and the clutch device may bedisconnected.

(7) In the aspect of any one of above mentioned (1) to (6), the clutchoperator may be a clutch lever, and the clutch operation amount sensormay detect a pivot angle of the clutch lever.

According to the aspect of above mentioned (1), since the method of thefeedback control is changed when the control parameter of the clutchcapacity reaches the control state change determination value, forexample, controls which are appropriate for the stroke region beforereaching the control state change determination value and for the loadcontrol region after reaching the control state change determinationvalue can be performed. For this reason, it is possible to improveconnection performance of the clutch device by quickening theconvergence of the control parameter. In addition, since the controlstate change determination value is set on the basis of the clutchoperation amount, for example, even when the oil path pressure lossextent of the clutch operation system is affected, connectionperformance of the clutch device can be improved similarly.

According to the aspect of above mentioned (2), since weighting of eachterms of the PID control of the clutch actuator is varied before andafter the control parameter of the clutch capacity reaches the controlstate change determination value, appropriate feedback control can beperformed. Specifically, the feedback control can be performed using theI term (integral term) main before the control parameter reaches thecontrol state change determination value, and the feedback control canbe performed using the P term (deviation term) main after the controlparameter reaches the control state change determination value. For thisreason, the convergence of the control parameter can be accelerated inthe load control region in a later stage of the clutch operation whilequickening a clutch stroke in the stroke region at the beginning of theclutch operation.

According to the aspect of above mentioned (3), since the method of thefeedback control is changed at a touch point at which it is switchedwhether to perform the power transmission or not to perform the powertransmission, the feedback control can be changed according to the statevariation of the clutch device, and it is possible to accelerate theconvergence of the control parameter while suppressing overshoot orhunting of the control parameter.

According to the aspect of above mentioned (4), since the control statechange determination value is varied depending on the clutch operationspeed (the lever operation speed), for example, even when the oil pathpressure loss extent of the clutch operation system is affected, it ispossible to vary the control state change determination value whileconsidering the loss extent. For this reason, it is possible toaccurately change the feedback control at the touch point at which it isswitched whether the clutch device performs the power transmission ornot to perform the power transmission.

According to the aspect of above mentioned (5), it is possible toincrease a degree of disposition freedom of the slave hydraulic pressuresensor, and even when the slave hydraulic pressure sensor and the slavecylinder are disposed at places separated from each other, it ispossible to accurately control the clutch capacity.

According to the aspect of above mentioned (6), even when there is adelay of transmission of a hydraulic pressure between the clutchactuator and the clutch device due to a flow resistance (pressure loss)of the hydraulic pressure, working responsiveness of the clutch devicecan be increased.

According to the aspect of above mentioned (7), a timing when a userrequires disconnection and connection of the clutch can be stably andaccurately detected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side view of a motorcycle of the embodiment.

FIG. 2 is a cross-sectional view of a gearbox and a change mechanism ofthe motorcycle.

FIG. 3 is a view for schematically explaining a clutch operating systemincluding a clutch actuator.

FIG. 4 is a block diagram of a gear shift system.

FIG. 5 is a graph showing variation in supplied hydraulic pressure ofthe clutch actuator.

FIG. 6 is a front view showing a shift arm and a shift operationdetection switch in an axial direction of a shift spindle.

FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. 6.

FIG. 8 is a front view corresponding to FIG. 6 in a state in which theshift operation detection switch has detected a shift operation.

FIG. 9 is a graph showing a correlation between a lever angle and atarget hydraulic pressure of the embodiment.

FIG. 10 is a flowchart showing processing of peak hold control of theembodiment.

FIG. 11A is a time chart of a comparative example for showing variationof a control parameter in a clutch control device of the embodiment.

FIG. 11B is a time chart showing variation of a control parameter in theclutch control device of the embodiment.

FIG. 12 is a graph showing a correlation between a clutch leveroperation amount, a sensor output voltage and a clutch capacity of theembodiment.

FIG. 13 is a view for explaining transition between clutch control modesof the embodiment.

FIG. 14 is a time chart showing variation of a control parameter in theclutch control device of the embodiment.

FIG. 15 is a flowchart upon switching of feedback processing of theembodiment.

FIG. 16 is a time chart showing variation of a control parameter in theclutch control device of the embodiment.

FIG. 17 is a graph showing a correlation between a lever operation speedand a touch point hydraulic pressure of the embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment of the present invention will be describedwith reference to the accompanying drawings. Further, directions offorward and rearward, leftward and rightward, and so on, in thefollowing description are the same as directions in a vehicle describedbelow unless the context clearly indicates otherwise. In addition, inappropriate places in the drawings used in the following description, anarrow FR indicates a forward direction with respect to a vehicle, anarrow LH indicates a leftward direction with respect to the vehicle, andan arrow UP indicates an upward direction with respect to the vehicle.

<Entire Vehicle>

As shown in FIG. 1, the embodiment is applied to a motorcycle 1 that isa saddle riding vehicle. A front wheel 2 of the motorcycle 1 issupported by lower end portions of a pair of left and right front forks3.

Upper sections of the left and right front forks 3 are supported by ahead pipe 6 provided at a front end portion of a vehicle body frame 5via a steering stem 4. A bar type steering handle 4 a is attached onto atop bridge of the steering stem 4.

The vehicle body frame 5 includes the head pipe 6, main tubes 7extending downward and rearward from the head pipe 6 at a center in avehicle width direction (a leftward and rightward direction), left andright pivot frames 8 that are connected to the lower sides of rear endportions of the main tubes 7, and a seat frame 9 that is connected torear sides of the main tubes 7 and the left and right pivot frames 8. Afront end portion of a swing arm 11 is swingably supported by the leftand right pivot frames 8. A rear wheel 12 of the motorcycle 1 issupported by a rear end portion of the swing arm 11.

A fuel tank 18 is supported above the left and right main tubes 7. Afront seat 19 and a rear seat cover 19 a that are arranged in a forwardand rearward direction are supported at behind the fuel tank 18 andabove the seat frame 9. The surroundings of the seat frame 9 are coveredwith a rear cowl 9 a.

A power unit PU that is a prime mover of the motorcycle 1 is suspendedbelow the left and right main tubes 7. The power unit PU is linked tothe rear wheel 12 via, for example, a chain type transmission mechanism.

The power unit PU integrally has a gearbox 21 disposed behind an engine(an internal combustion engine) 13 disposed in front of the power unitPU. The engine 13 is, for example, a multiple-cylinder engine in which arotation axis of a crankshaft 14 is in the leftward and rightwarddirection (the vehicle width direction). In the engine 13, a cylinder 16stands up at a front upper side of a crankcase 15. A rear section of thecrankcase 15 is a gearbox case 17 that accommodates the gearbox 21.

<Gearbox>

As shown in FIG. 2, the gearbox 21 is a stepped transmission having amain shaft 22, a counter shaft 23, and a shifting gear group 24 thatbridges both of the shafts 22 and 23. The counter shaft 23 constitutesoutput shafts of the gearbox 21 and the power unit PU. An end portion ofthe counter shaft 23 protrudes from a rear left side of the crankcase15, and is connected to the rear wheel 12 via the chain typetransmission mechanism.

The shifting gear group 24 has gears corresponding to the number ofvariable speed levels supported by the shafts 22 and 23. The gearbox 21is of a constant mesh type in which gear pairs to which the shiftinggear group 24 corresponds are normally meshed between the shafts 22 and23. A plurality of gears supported by the shafts 22 and 23 areclassified into a free gear that is rotatable with respect to acorresponding shaft, and a slide gear (a shifter) spline-fitted to acorresponding shaft. A convex dog is formed on one of the free gear andthe slide gear in an axial direction, and a concave slot is formed inthe other gear in the axial direction such that the dog is engaged withthe slot. That is, the gearbox 21 is a so-called dog mission.

Referring also to FIG. 3, the main shaft 22 and the counter shaft 23 ofthe gearbox 21 are disposed behind the crankshaft 14 in the forward andrearward direction. A clutch device 26 operated by a clutch actuator 50is disposed coaxially with a right end portion of the main shaft 22. Theclutch device 26 is, for example, a wet multiplate clutch that is aso-called normal open clutch. That is, the clutch device 26 is in aconnection state in which power transmission is possible due to supplyof a hydraulic pressure from the clutch actuator 50, and returns to adisconnection state in which power transmission is not possible whenthere is no supply of a hydraulic pressure from the clutch actuator 50.

Referring to FIG. 2, the rotary power of the crankshaft 14 istransmitted to the main shaft 22 via the clutch device 26, andtransmitted from the main shaft 22 to the counter shaft 23 via anarbitrary gear pair of the shifting gear group 24. A drive sprocket 27of the chain type transmission mechanism is attached to a left endportion of the counter shaft 23 protruding toward a rear left side ofthe crankcase 15. A change mechanism 25 configured to switch a gear pairof the shifting gear group 24 is accommodated in the gearbox 21 on arear upper side thereof. The change mechanism 25 operates a plurality ofshift forks 36 a according to a pattern of lead grooves formed in anouter circumference thereof due to rotation of a hollow cylindricalshift drum 36 parallel to both of the shafts 22 and 23, and switches agear pair of the shifting gear group 24 used for power transmissionbetween the shafts 22 and 23.

The change mechanism 25 has a shift spindle 31 parallel to the shiftdrum 36.

Upon rotation of the shift spindle 31, a shift arm 31 a fixed to theshift spindle 31 rotates the shift drum 36, moves the shift forks 36 aaccording to a pattern of the lead groove in the axial direction, andswitches a gear pair that enables power transmission in the shiftinggear group 24 (i.e., a variable speed level is switched).

The shift spindle 31 has a shaft outer portion 31 b protruding outward(leftward) from the crankcase 15 in the vehicle width direction suchthat the change mechanism 25 is operable. A shift load sensor 42 (ashift operation detection means) is coaxially attached to the shaftouter portion 31 b of the shift spindle 31 (see FIG. 1). A swing lever33 is attached to the shaft outer portion 31 b of the shift spindle 31(or a rotation axis of the shift load sensor 42). The swing lever 33extends rearward from a base end portion 33 a fixed to the shift spindle31 (or a rotation axis) using a clamp, and an upper end portion of alink rod 34 is swingably connected to a tip portion 33 b of the swinglever 33 via an upper ball joint 34 a. A lower end portion of the linkrod 34 is swingably connected to a shift pedal 32 that is operated by adriver's foot via a lower ball joint (not shown).

As shown in FIG. 1, the shift pedal 32 has a front end portion that isvertically swingably supported by a lower section of the crankcase 15via a shaft in the leftward and rightward direction. A pedal section onwhich a tip of a driver's foot placed on a step 32 a is put is installedon a rear end portion of the shift pedal 32, and a lower end portion ofthe link rod 34 is connected to an intermediate section of the shiftpedal 32 in the forward and rearward direction.

As shown in FIG. 2, a shift change apparatus 35 including the shiftpedal 32, the link rod 34 and the change mechanism 25 and configured toswitch a variable speed level gear of the gearbox 21 is provided. In theshift change apparatus 35, an assembly (the shift drum 36, the shiftforks 36 a, and so on) configured to switch a variable speed level ofthe gearbox 21 is referred to as a transmission working part 35 a, andthe assembly (the shift spindle 31, the shift arm 31 a, and so on) intowhich a shifting operation to the shift pedal 32 is input and configuredto rotate about a shaft of the shift spindle 31 and transmit therotation to the transmission working part 35 a is referred to as ashifting operation receiving part 35 b.

Here, the motorcycle 1 employs a so-called semi-automatic gear shiftsystem (an automatic clutch type gear shift system) in which a driverperforms only a shifting operation of the gearbox 21 (a foot operationof the shift pedal 32), and a disconnection and connection operation ofthe clutch device 26 is automatically performed through electric controlaccording to an operation of the shift pedal 32.

<Gear Shift System>

As shown in FIG. 4, the gear shift system includes the clutch actuator50, an electronic control unit 60 (ECU, a control device) and varioussensors 41 to 45.

The ECU 60 controls operations of an ignition apparatus 46 and a fuelinjection apparatus 47 while controlling an operation of the clutchactuator 50 on the basis of detection information from a gear positionsensor 41 configured to detect a variable speed level from a rotationangle of the shift drum 36 and a shift load sensor (for example a torquesensor) 42 configured to detect an operation torque input to the shiftspindle 31, and various types of vehicle state detection information orthe like from a throttle opening angle sensor 43, a vehicle speed sensor44, an engine rotational speed sensor 45, and so on. Detectioninformation from hydraulic pressure sensors 57 and 58, and a shiftoperation detection switch (a shift neutral switch) 48, which will bedescribed below, is also input to the ECU 60.

The ECU 60 includes a memory 62 such as a read only memory (ROM), arandom access memory (RAM), or the like, in addition to a centralprocessing unit (CPU).

In addition, the ECU 60 includes a hydraulic pressure controller (aclutch controller) 61, a function of which will be described below.

Referring also to FIG. 3, the clutch actuator 50 can control a liquidpressure that disconnects and connects the clutch device 26 bycontrolling an operation thereof using the ECU 60. The clutch actuator50 includes an electric motor 52 (hereinafter, simply referred to as themotor 52) serving as a drive source, and a master cylinder 51 driven bythe motor 52. The clutch actuator 50 constitutes an integrated clutchcontroller 50A together with a hydraulic pressure circuit apparatus 53installed between the master cylinder 51 and a hydraulic pressuresupply/discharge port 50 p.

The ECU 60 calculates a target value (a target hydraulic pressure) of ahydraulic pressure supplied to a slave cylinder 28 for disconnecting andconnecting the clutch device 26 on the basis of a preset calculationprogram, and controls the clutch controller 50A such that a hydraulicpressure (a slave hydraulic pressure) on the side of the slave cylinder28 detected by the downstream-side hydraulic pressure sensor 58approaches a target hydraulic pressure.

The master cylinder 51 can stroke a piston 51 b in a cylinder main body51 a through driving of the motor 52, and working oil in the cylindermain body 51 a can be supplied to or discharged from the slave cylinder28. Reference numeral 55 in the drawings designates a ball screwmechanism serving as a conversion mechanism, reference numeral 54designates a transmission mechanism that bridges between the motor 52and the conversion mechanism 55, and reference numeral 51 e designates areservoir connected to the master cylinder 51.

The hydraulic pressure circuit apparatus 53 has a valve mechanism (asolenoid valve 56) configured to open or block an intermediate area of amain oil path (a hydraulic pressure supply/discharge oil path) 53 mextending from the master cylinder 51 toward the clutch device 26 (theslave cylinder 28). The main oil path 53 m of the hydraulic pressurecircuit apparatus 53 is divided into an upstream side oil path 53 awhich is at the master cylinder 51 side with respect to the solenoidvalve 56 and a downstream side oil path 53 b which is at the slavecylinder 28 side with respect to the solenoid valve 56. The hydraulicpressure circuit apparatus 53 further includes a bypass oil path 53 cconfigured to bypass the solenoid valve 56 and to communicate theupstream side oil path 53 a and the downstream side oil path 53 b.

The solenoid valve 56 is a so-called normal open valve. A one-way valve53 c 1 configured to allow working oil to flow only in a direction froman upstream side to a downstream side is installed in the bypass oilpath 53 c. The upstream-side hydraulic pressure sensor 57 configured todetect a hydraulic pressure of the upstream side oil path 53 a isinstalled at the upstream of the solenoid valve 56. The downstream-sidehydraulic pressure sensor 58 configured to detect a hydraulic pressureof the downstream side oil path 53 b is installed at the downstream ofthe solenoid valve 56.

As shown in FIG. 1, the clutch controller 50A is accommodated in, forexample, the rear cowl 9 a. The slave cylinder 28 is attached to a rearleft side of the crankcase 15. The clutch controller 50A and the slavecylinder 28 are connected to each other via a hydraulic pressurepipeline 53 e (see FIG. 3).

As shown in FIG. 2, the slave cylinder 28 is disposed coaxially with themain shaft 22 on a left side thereof. The slave cylinder 28 presses apush rod 28 a passing through the main shaft 22 rightward when ahydraulic pressure from the clutch actuator 50 is supplied. The slavecylinder 28 operates the clutch device 26 into a connection state viathe push rod 28 a by pressing the push rod 28 a rightward. The slavecylinder 28 releases pressing of the push rod 28 a and returns theclutch device 26 to a disconnection state when there is no supply of thehydraulic pressure.

While a hydraulic pressure needs to be continuously supplied to maintainthe clutch device 26 in a connection state, electric power iscorrespondingly consumed. Here, as shown in FIG. 3, the solenoid valve56 is installed in the hydraulic pressure circuit apparatus 53 of theclutch controller 50A, and the solenoid valve 56 is closed after supplyof a hydraulic pressure toward the clutch device 26. Accordingly, energyconsumption is minimized by a configuration of maintaining a hydraulicpressure at the clutch device 26 side and supplementing the hydraulicpressure according to decrease in pressure (recharging a pressureaccording to an amount of leakage).

<Clutch Control>

Next, an action of a clutch control system will be described withreference to a graph of FIG. 5. In the graph of FIG. 5, a vertical axisrepresents a supplied hydraulic pressure detected by the downstream-sidehydraulic pressure sensor 58, and a lateral axis represents an elapsedtime.

Upon stoppage (upon idling) of the motorcycle 1, both of the motor 52and the solenoid valve 56 controlled by the ECU 60 are in a state inwhich supply of electric power is cut off. That is, the motor 52 is in astopped state, and the solenoid valve 56 is in an open state. Here, theslave cylinder 28 side (a downstream side) is in a state of having apressure lower than a touch point hydraulic pressure TP, and the clutchdevice 26 is in a disengaged state (a disconnection state, a releasestate). This state corresponds to a region A in FIG. 5.

Upon departure of the motorcycle 1, when a rotational number of theengine 13 is increased, electric power is supplied only to the motor 52,and a hydraulic pressure is supplied from the master cylinder 51 to theslave cylinder 28 via the solenoid valve 56 in an open state. When ahydraulic pressure on a side of the slave cylinder 28 (a downstreamside) is increased to the touch point hydraulic pressure TP or more,engagement of the clutch device 26 is started, and the clutch device 26becomes in a half clutch state in which some of power can betransmitted. Accordingly, smooth departure of the motorcycle 1 becomespossible. This state corresponds to a region B in FIG. 5.

Then, when a difference between input rotation and output rotation ofthe clutch device 26 is reduced and a hydraulic pressure on a side ofthe slave cylinder 28 (the downstream side) reaches a lower limitholding hydraulic pressure LP, engagement of the clutch device 26 isshifted to a locked state, and a driving force of the engine 13 isentirely transmitted to the gearbox 21. This state corresponds to aregion C in FIG. 5.

When a hydraulic pressure is supplied from the master cylinder 51 sidetoward the slave cylinder 28, the solenoid valve 56 is in an open state,the motor 52 is energized to drive in a normal rotation direction, andthe master cylinder 51 is pressurized. Accordingly, a hydraulic pressureon a side of the slave cylinder 28 is adjusted to a clutch-engagementhydraulic pressure. Here, driving of the clutch actuator 50 isfeedback-controlled on the basis of a detected hydraulic pressure of thedownstream-side hydraulic pressure sensor 58.

Then, when a hydraulic pressure on the side of the slave cylinder 28(the downstream side) reaches an upper limit holding hydraulic pressureHP, electric power is supplied to the solenoid valve 56 to close thesolenoid valve 56, and simultaneously, supply of electric power to themotor 52 is stopped and generation of a hydraulic pressure is stopped.That is, when the upstream side is in a low pressure state since thehydraulic pressure has been released, on the other hand, the downstreamside is maintained in a high pressure state (the upper limit holdinghydraulic pressure HP). Accordingly, the clutch device 26 is maintainedin an engaged state without generation of hydraulic pressure from themaster cylinder 51, and electric power consumption can be minimizedwhile enabling traveling of the motorcycle 1.

Here, depending on a shifting operation, there may be a situation inwhich the clutch device 26 is shifted immediately after inputting thehydraulic pressure. In this case, before the solenoid valve 56 is closedand the upstream side is in a low pressure state, the motor 52 is drivenin a reverse direction while the solenoid valve 56 is in an open state,a reservoir 51 e is caused to communicate with the master cylinder 51while the master cylinder 51 is decompressed, and a hydraulic pressureon the side of the clutch device 26 is relieved toward the mastercylinder 51. Here, driving of the clutch actuator 50 isfeedback-controlled on the basis of a detected hydraulic pressure of theupstream-side hydraulic pressure sensor 57.

Even in a state in which the solenoid valve 56 is closed and the clutchdevice 26 is maintained in a fastened state, as shown in a region D inFIG. 5, a hydraulic pressure on the downstream side will graduallydecrease (leak). That is, a hydraulic pressure on the downstream sidewill gradually decrease due to causes such as a leakage of a hydraulicpressure or a decrease in temperature due to deformation or the like ofseals of the solenoid valve 56 and the one-way valve 53 c 1.

On the other hand, as shown in a region E in FIG. 5, there is also acase in which a hydraulic pressure on the downstream side is increaseddue to an increase in temperature or the like.

If it is a small hydraulic pressure fluctuation on the downstream side,it is possible to absorb by an accumulator (not shown), and it is notnecessary to increase the electric power consumption by operating themotor 52 and the solenoid valve 56 every time the hydraulic pressurefluctuates.

As shown in the region E in FIG. 5, when a hydraulic pressure on thedownstream side is increased to the upper limit holding hydraulicpressure HP, by decreasing the supply of electric power to the solenoidvalve 56 or the like, the solenoid valve 56 is gradually brought into anopen state, and the hydraulic pressure on the downstream is relievedtoward the upstream side.

As shown in a region F in FIG. 5, when a hydraulic pressure on thedownstream side is decreased to the lower limit holding hydraulicpressure LP, the solenoid valve 56 starts supply of electric power tothe motor 52 while being closed, and a hydraulic pressure on theupstream side is increased. When the hydraulic pressure on the upstreamside exceeds the hydraulic pressure on the downstream side, thehydraulic pressure is supplemented (recharged) toward the downstreamside via the bypass oil path 53 c and the one-way valve 53 c 1. When thehydraulic pressure on the downstream side reaches the upper limitholding hydraulic pressure HP, supply of electric power to the motor 52is stopped and generation of the hydraulic pressure is stopped.Accordingly, the hydraulic pressure on the downstream side is maintainedbetween the upper limit holding hydraulic pressure HP and the lowerlimit holding hydraulic pressure LP, and the clutch device 26 ismaintained in a fastened state.

When the gearbox 21 is at a neutral position upon stoppage of themotorcycle 1, supply of electric power to the motor 52 and the solenoidvalve 56 is also stopped. Accordingly, the master cylinder 51 stopsgeneration of a hydraulic pressure and stops supply of a hydraulicpressure to the slave cylinder 28. The solenoid valve 56 becomes in anopen state, and a hydraulic pressure in the downstream side oil path 53b is returned to the reservoir 51 e. As described above, the slavecylinder 28 side (the downstream side) is in a state of a pressure lowerthan the touch point hydraulic pressure TP, and the clutch device 26becomes in a disengaged state. This state corresponds to regions G and Hin FIG. 5.

On the other hand, if the gearbox 21 is kept in an in-gear state uponstoppage of the motorcycle 1, a standby state in which a standbyhydraulic pressure WP is applied at the slave cylinder 28 side isestablished.

The standby hydraulic pressure WP is a hydraulic pressure that isslightly lower than the touch point hydraulic pressure TP at whichconnection of the clutch device 26 starts, and a hydraulic pressure (ahydraulic pressure applied to the regions A and H in FIG. 5) at whichthe clutch device 26 is not connected. Invalid filling of the clutchdevice 26 (rattling of each part or cancellation of a reaction force ofan operation, application of pre-compression to a hydraulic path, and soon) becomes possible due to application of the standby hydraulicpressure WP, working responsiveness upon connection of the clutch device26 is increased.

<Shift Control>

Next, shift control of the motorcycle 1 will be described.

The motorcycle 1 of the embodiment performs control of decreasing thestandby hydraulic pressure WP supplied to the slave cylinder 28 when ashift operation from a first to a neutral position with respect to theshift pedal 32 is performed in a state in which a gear position of thegearbox 21 is in a first speed in-gear state and in an in-gear stoppagestate in which a vehicle speed is less than a set value that correspondsto stoppage of the motorcycle.

Here, when the motorcycle 1 is in a stoppage state and a gear positionof the gearbox 21 is disposed at any variable speed level position otherthan the neutral position, i.e., when the gearbox 21 is in an in-gearstoppage state, the preset standby hydraulic pressure WP is supplied tothe slave cylinder 28.

The standby hydraulic pressure WP is set to a first set value P1 (seeFIG. 5) that is a standard standby hydraulic pressure at a normal time(in a case of a non-detection state in which a shifting operation of theshift pedal 32 is not detected). Accordingly, the clutch device 26 is ina standby state in which the invalid filling is performed,responsiveness upon clutch engagement is increased. That is, when adriver increases a throttle opening angle and increases a rotationalnumber of the engine 13, immediate engagement of the clutch device 26 isstarted due to supply of a hydraulic pressure to the slave cylinder 28,and rapid departure acceleration of the motorcycle 1 is realized.

The motorcycle 1 includes a shift operation detection switch 48separately from the shift load sensor 42 in order to detect a shiftoperation of a driver with respect to the shift pedal 32.

Then, in the in-gear stoppage state, when the shift operation detectionswitch 48 detects a shift operation from a first speed to a neutralposition, the hydraulic pressure controller 61 performs control ofsetting the standby hydraulic pressure WP to a second set value P2 (alow pressure standby hydraulic pressure, see FIG. 5) which is lower thanthe first set value P1 before performing a shifting operation.

When the gearbox 21 is in an in-gear state, since a standard standbyhydraulic pressure corresponding to the first set value P1 is suppliedto the slave cylinder 28 at a normal time, a slight, so-called, dragwill occur in the clutch device 26. Here, a dog and a slot (a dog hole)meshing with each other in a dog clutch of the gearbox 21 press eachother in a rotational direction, and a resistance in engagement releaseoccurs and a shift operation may become heavy. In this case, when thestandby hydraulic pressure WP supplied to the slave cylinder 28 islowered to a low pressure standby hydraulic pressure corresponding tothe second set value P2, engagement of the dog and the slot can beeasily released, and it is possible to make a shift operation light.

<Shift Operation Detection Switch>

As shown in FIG. 6 and FIG. 7, the shift operation detection switch 48is installed so as to face with an outer circumferential end portion ofthe shift arm 31 a, which extends outward in a radial direction from arotational center (an axial center) C1 of the shift spindle 31, in aradial direction. An arrow SUP in FIG. 6 indicates a shift-up side in arotational direction of the shift spindle 31, and an arrow SDN indicatesa shift-down side in the rotational direction of the shift spindle 31.

Referring to FIG. 6, the shift arm 31 a extends along an extensionreference line L1 passing through the axial center C1. The shiftoperation detection switch 48 is supported on a side of the gearbox case17, and the shift arm 31 a relatively rotates with respect to the shiftoperation detection switch 48.

The shift operation detection switch 48 is formed in a columnar shape,and a centerline L2 is arranged so as to extend along with the radialdirection of the shift spindle 31. The shift operation detection switch48 has a probe 48 s that strokes along the centerline L2. The probe 48 sprotrudes toward a member 49 to be detected installed on an outercircumferential end portion of the shift arm 31 a.

The shift arm 31 a sets a neutral position D1 in the centerline L2 ofthe shift operation detection switch 48 which is set at a position thatcoincides with an extension line of the extension reference line L1. Theshift arm 31 a is biased toward the neutral position D1 by a returnspring (not shown). The member 49 to be detected is installed on anouter circumferential end portion of the shift arm 31 a while facing theshift operation detection switch 48. The member 49 to be detected isformed in a convex V shape on an outer side in the radial direction, andinstalled in a shape symmetrical with respect to the extension referenceline L1. The member 49 to be detected has a protrusion top portion 49 tdirected toward an outer side in the radial direction, and a pair ofinclined surface portions 49 s formed at both sides of the protrusiontop portion 49 t in the rotational direction of the shift spindle 31.The pair of inclined surface portions 49 s are disposed substantiallyperpendicular to each other. Round chamfering having the same radius asa spherical tip surface of the probe 48 s of the shift operationdetection switch 48 is applied on the protrusion top portion 49 t.

As shown in FIG. 6, the shift arm 31 a is disposed at the neutralposition D1 in a state in which an operation load from the shift pedal32 is not applied. Here, the protrusion top portion 49 t of the member49 to be detected confronts the probe 48 s of the shift operationdetection switch 48 in the radial direction. Accordingly, the probe 48 sof the shift operation detection switch 48 is in a retracted state, andthe shift operation detection switch 48 is in an ON or OFF state (in thedrawing, an ON state).

On the other hand, as shown in FIG. 8, when an operation load is appliedto the shift pedal 32 and the shift spindle 31 is rotated, the shift arm31 a is rotated integrally therewith. In FIG. 8, the shift spindle 31and the shift arm 31 a are rotated toward a shift-up side. When theshift arm 31 a is rotated, the protrusion top portion 49 t of the member49 to be detected is displaced with respect to the probe 48 s of theshift operation detection switch 48 in a circumferential direction.Then, the probe 48 s is varied to a protrusion state while slidingcontacting with one of the pair of inclined surface portions 49 s, andan ON/OFF state of the shift operation detection switch 48 is switched.Accordingly, the ECU 60 detects rotation of the shift spindle 31 fromthe neutral position D1, i.e., a shifting operation to the shift pedal32. A rotation position (a shift operation detection position) D2 of theshift arm 31 a at this time is a position rotated from the neutralposition D1 by a small angle θ1 of 2 to 3 degrees.

Further, while it is shown that detection of ON or OFF is performed suchthat ON is detected when the probe 48 s retreats and OFF is detectedwhen the probe 48 s protrudes in FIG. 6 and FIG. 8, detection of ON orOFF may be performed such that ON is detected when the probe 48 s comesin contact with the inclined surface portions 49 s and OFF is detectedwhen the probe 48 s does not come in contact with the inclined surfaceportions 49 s.

In this way, since the member 49 to be detected having the protrusiontop portion 49 t is installed on the outer circumferential end portionof the shift arm 31 a extending closer to the outer circumference thanto the shift spindle 31, the shift operation detection switch 48sensitively detects slight rotation of the shift spindle 31 due to ashifting operation of the shift pedal 32. In addition, in comparisonwith the case in which a shifting operation is detected from a shiftoperation load, even when a shifting operation is detected from arotation position of the shift arm 31 a fixed to the shift spindle 31,sensitive detection becomes possible. In addition, in comparison withthe case in which displacement of a working member (the shift drum 36 orthe like) separate from the shift spindle 31 is detected, a shiftingoperation can be more directly detected.

<Clutch Control Mode>

As shown in FIG. 13, a clutch control device 60A of the embodiment hasthree types of clutch control modes. The clutch control modes areappropriately shifted according to operations of a clutch control modeselection switch 59 (see FIG. 4) and the clutch lever 4 b (see FIG. 1)between the three types of modes of an automatic mode M1 of performingautomated control, a manual mode M2 of performing a manual operation anda manual intervention mode M3 of performing a temporary manualoperation. Further, an object including the manual mode M2 and themanual intervention mode M3 is referred to as a manual system M2A.

The automatic mode M1 is a mode of controlling the clutch device 26 bycalculating a clutch capacity appropriate for a traveling state throughautomatic departure and shift control. The manual mode M2 is a mode ofcontrolling the clutch device 26 by calculating a clutch capacityaccording to a clutch operation instruction from an occupant. The manualintervention mode M3 is a temporary manual operation mode of controllingthe clutch device 26 by receiving a clutch operation instruction from anoccupant during the automatic mode M1 and calculating a clutch capacityfrom the clutch operation instruction. Further, the modes are set suchthat when an occupant stops (perfectly releases) an operation of aclutch lever 4 b during the manual intervention mode M3 it returns tothe automatic mode M1.

The clutch control device 60A of the embodiment starts control from aclutch-off state (a disconnection state) in the automatic mode M1 uponstarting of the system. In addition, the clutch control device 60A isset to return to the clutch-off in the automatic mode M1 since a clutchoperation is unnecessary upon stoppage of the engine 13.

The automatic mode M1 basically performs the clutch controlautomatically, and allows the motorcycle 1 to travel with no leveroperation. In the automatic mode M1, a clutch capacity is controlled bya throttle opening angle, an engine rotational number, a vehicle speedand a shift sensor output. Accordingly, the motorcycle 1 can be startedwithout engine stall with only a throttle operation and can be shiftedwith only a shift operation. However, there is a situation in which theclutch device 26 is automatically disconnected upon an extremely lowspeed equivalent to idling. In addition, in the automatic mode M1, it isswitched to the manual intervention mode M3 by grasping the clutch lever4 b, and it is also possible to arbitrarily disconnect the clutch device26.

Meanwhile, in the manual mode M2, a clutch capacity is controlledaccording to a lever operation by an occupant. The automatic mode M1 andthe manual mode M2 can be switched by operating the clutch control modeselection switch 59 (see FIG. 4) during stoppage. Further, the clutchcontrol device 60A may include an indicator indicating that a leveroperation is effective upon shifting to the manual system M2A (themanual mode M2 or the manual intervention mode M3).

The manual mode M2 basically performs the clutch control manually, and aclutch hydraulic pressure can be controlled according to an actuationangle of the clutch lever 4 b. Accordingly, it is possible to controldisconnection and connection of the clutch device 26 as an occupantdesires, and it is possible to connect the clutch device 26 to travelthe motorcycle even at an extremely low speed equivalent to idling.However, an engine stall may occur according to a way of leveroperation, and an automatic departure depending solely on a throttleoperation is also not possible. Further, even in the manual mode M2,clutch control is automatically intervened upon a shift operation.

While disconnection and connection of the clutch device 26 is performedautomatically by the clutch actuator 50 in the automatic mode M1, amanual operation can be temporarily intervened to the automated controlof the clutch device 26 by performing a manual clutch operation withrespect to the clutch lever 4 b (the manual intervention mode M3).

As shown in FIG. 12, an operation amount (a pivot angle) of the clutchlever 4 b and an output value of a clutch lever operation amount sensor4 c are in a proportional relationship (correlation) with each other.The ECU 60 calculates a target hydraulic pressure of the clutch device26 on the basis of the output value of the clutch lever operation amountsensor 4 c.

Referring also to FIG. 11A, even when a target hydraulic pressure iscalculated on the basis of an operation amount (a clutch lever angle) ofthe clutch lever 4 b, an actual hydraulic pressure (a slave hydraulicpressure) generated in the slave cylinder 28 follows the targethydraulic pressure with delay. That is, since a pressure loss occurs inthe hydraulic pressure pipeline between the clutch actuator 50 and theslave cylinder 28, a delay occurs in following a slave hydraulicpressure (that is, a clutch gap) which is a control target hydraulicpressure with respect to target hydraulic pressure on the basis of alever operation amount. In this way, when a delay of the control targethydraulic pressure with respect to the target hydraulic pressure occurs,a driver may feel badness of responsiveness of the clutch device 26.Control of solving this point will be described below.

Further, while the slave hydraulic pressure is detected by thedownstream-side hydraulic pressure sensor 58, a difference with ahydraulic pressure actually applied to the clutch device 26 (the slavecylinder 28) occurs. This is because a pressure loss occurs in an oilpath from the downstream-side hydraulic pressure sensor 58 to the slavecylinder 28. In particular, when the hydraulic pressure is abruptlyvaried, a difference between a slave hydraulic pressure detected by thedownstream-side hydraulic pressure sensor 58 and a slave hydraulicpressure actually applied to the clutch device 26 is increased. When thepressure is increased, a hydraulic pressure actually applied to theclutch device 26 is increased with delay with respect to the hydraulicpressure detected by the downstream-side hydraulic pressure sensor 58.

<Manual Clutch Operation>

As shown in FIG. 1, the clutch lever 4 b serving as a clutch manualoperator is attached to a base end side (an inner side in the vehiclewidth direction) of a left grip of the steering handle 4 a. The clutchlever 4 b does not have any mechanical connection with the clutch device26 which uses a cable, a hydraulic pressure, or the like and functionsas an operator configured to transmit a clutch operation requirementsignal to the ECU 60. That is, the motorcycle 1 employs a clutch-by-wiresystem configured to electrically connect the clutch lever 4 b and theclutch device 26.

Referring also to FIG. 4, the clutch lever operation amount sensor 4 cconfigured to detect an operation amount (a pivot angle) of the clutchlever 4 b is installed integrally with the clutch lever 4 b. The clutchlever operation amount sensor 4 c converts an operation amount of theclutch lever 4 b into an electrical signal and outputs the convertedelectrical signal.

In a state in which an operation of the clutch lever 4 b is effective(the manual system M2A), the ECU 60 drives the clutch actuator 50 basedon the output of the clutch lever operation amount sensor 4 c. Further,the clutch lever 4 b and the clutch lever operation amount sensor 4 cmay be integrated with each other or may be separate from each other.

The motorcycle 1 includes the clutch control mode selection switch 59configured to switch a control mode of a clutch operation. The clutchcontrol mode selection switch 59 can arbitrarily perform switchingbetween the automatic mode M1 of automatically performing clutch controland the manual mode M2 of manually performing clutch control accordingto an operation of the clutch lever 4 b under a predetermined condition.For example, the clutch control mode selection switch 59 is installed ona handle switch attached to the steering handle 4 a. Accordingly, anoccupant can easily operate the clutch operation upon a normal driving.

Referring also to FIG. 12, the clutch lever 4 b is pivotable between arelease state, which is a state in which the clutch lever 4 b isreleased without being under a gripping operation of an occupant and ispivoted toward a clutch connection side, and an abutting state, which isa state in which the clutch lever 4 b is pivoted toward a grip side (aclutch disconnection side) by the gripping of an occupant and is abutagainst the grip. The clutch lever 4 b is biased to return to a releasestate that is an initial position when released from a grippingoperation by an occupant.

For example, the clutch lever operation amount sensor 4 c is configuredto set an output voltage to zero in a state in which the clutch lever 4b is completely gripped (an abutting state) and to increase an outputvoltage from the abutting state according to a release operation of theclutch lever 4 b (an operation toward a clutch connection side). In theembodiment, among the output voltage of the clutch lever operationamount sensor 4 c, a range that excludes a lever margin which is presentat the beginning of gripping the clutch lever 4 b and an abutting marginwhich secures a gap having a size in which a finger can be placedbetween the gripped lever and the grip is set to an effective voltagerange (an effective operation range of the clutch lever 4 b).

Specifically, a range from an operation amount S1, which is an operationamount in which the clutch lever 4 b is released only by the abuttingmargin from the abutting state of the clutch lever 4 b, to an operationamount S2, which is an operation amount in which the clutch lever 4 b isreleased until a lever margin starts, is set so as to correspond to arange from a lower limit value E1 to an upper limit value E2 of aneffective voltage. The range from the lower limit value E1 to the upperlimit value E2 corresponds to a range from zero to MAX of a calculatedvalue of a manual operation clutch capacity in a proportional relation.Accordingly, an influence of mechanical ratting, a sensor variation, orthe like, can be decreased, and reliability of a clutch driving amountrequired by a manual operation can be increased. Further, a value at theoperation amount S1 of the clutch lever 4 b may be set as the upperlimit value E2 of the effective voltage, and a value at the operationamount S2 may be set as the lower limit value E1.

<Peak Hold Control>

Referring to FIG. 11B, the clutch control device 60A of the embodimentperforms peak hold control, which will be described below in detail,when a connection operation speed (a clutch operation speed) of theclutch lever 4 b is high. The peak hold control changes a control targetvalue (a target hydraulic pressure) of a clutch capacity toward a clutchconnection side with respect to an operation target hydraulic pressurePv corresponding to an operation amount of the clutch lever 4 b when aconnection operation speed of the clutch lever 4 b is high. Accordingly,when a connection operation speed of the clutch lever 4 b is high, atarget hydraulic pressure can be increased more rapidly (the clutchdevice 26 can be connected more rapidly).

Referring to FIG. 9, in a graph in FIG. 9, a vertical axis indicates atarget hydraulic pressure of clutch control (a control target value of aslave hydraulic pressure), and a lateral axis indicates a pivot angle ofthe clutch lever 4 b (a lever angle). In addition, a lever angle D3represents a release lever angle when the clutch lever 4 b is separatedand released, and a lever angle D4 represents an abutting-lever anglewhen the clutch lever 4 b is gripped to abut against the grip (or whenpivoted to the vicinity of abutting against the grip). The clutch device26 is in a connection state in which sliding is 0 when the clutch lever4 b is in a range from the release lever angle D3 to a lever margin D3a, and the clutch device 26 is in a disconnection state in which atransmission torque is 0 when the clutch lever 4 b is in a range fromthe lever angle D4 to an abutting margin D4 a.

In addition, a range PH of a target hydraulic pressure represents a peakhold hydraulic pressure range in which peak hold control is performed.In addition, a target hydraulic pressure P3 represents an upper limithydraulic pressure of the peak hold hydraulic pressure range PH, and atarget hydraulic pressure P4 represents a lower limit hydraulic pressureof the peak hold hydraulic pressure range PH. The peak hold hydraulicpressure range PH corresponds to a range that becomes a half clutchstate in which the clutch device 26 can transmit a part of power. Thepeak hold hydraulic pressure range PH corresponds to a range until ahydraulic pressure on a side of the slave cylinder 28 (the downstreamside) detected by the downstream-side hydraulic pressure sensor 58 isincreased to substantially the touch point hydraulic pressure TP or moreand reaches a hydraulic pressure at which the clutch device 26 iscompletely fastened (a clutch gap is 0).

In an initial stage (a lever release initial stage, a range of theabutting margin D4 a) in which the clutch lever 4 b is released from theabutting lever angle D4, the target hydraulic pressure is increasedrelatively rapidly according to variation of the lever angle. In thelever release initial stage, a way of varying a target hydraulicpressure is constant regardless of a lever operation speed. Then, in thepeak hold hydraulic pressure range PH after exceeding the lever releaseinitial stage, a way of varying a target hydraulic pressure is variedaccording to a lever operation speed.

Further, in a final stage of the lever release initial stage, the targethydraulic pressure is included in the peak hold hydraulic pressure rangePH by an extent of +a (exceeds the lower limit hydraulic pressure P4 ofthe peak hold hydraulic pressure range PH by an extent of +α).Accordingly, in a state in which a target hydraulic pressure exceeds alever release initial stage, the slave hydraulic pressure following thetarget hydraulic pressure with delay also reaches the peak holdhydraulic pressure range PH.

The ECU 60 starts change control of a target hydraulic pressure map whenthe target hydraulic pressure exceeds the lower limit hydraulic pressureP4 of the peak hold hydraulic pressure range PH.

Here, the ECU 60 calculates a lever operation speed at a prescribedcontrol period, and updates the fastest value of the lever operationspeed when the current lever operation speed is greater than the leveroperation speed until now. Here, the target hydraulic pressure map inthe peak hold hydraulic pressure range PH is shifted to a high speedside map MPH.

Meanwhile, the ECU 60 maintains the present fastest value of the leveroperation speed in this state when the current lever operation speed islater than the lever operation speed until now. Here, the targethydraulic pressure map in the peak hold hydraulic pressure range PH isnot shifted to a low speed side map MPL, and the map MPH according tothe present fastest value in this state is maintained.

Hereinafter, the above-mentioned series of control is referred to aspeak hold control.

The ECU 60 returns the target hydraulic pressure map to the low speedside map MPL (an actual speed map, corresponding to the operation targethydraulic pressure Pv) when the slave hydraulic pressure exceeds thepeak hold hydraulic pressure range PH.

That is, the fact that the slave hydraulic pressure exceeds the peakhold hydraulic pressure range PH is a reset condition of the peak holdcontrol.

Further, while the peak hold control of the embodiment exemplarily showsupon the clutch connection operation, the peak hold control may beapplied upon the clutch disconnection operation. Accordingly, when theclutch disconnection operation speed is high, a control target value ofa clutch capacity is varied toward a clutch disconnection side, and aslave hydraulic pressure can be decreased more rapidly (the clutchdevice 26 can be disconnected more rapidly).

Next, an example of processing performed by the ECU 60 upon the peakhold control will be described with reference to a flowchart in FIG. 10.The control flow is repeatedly performed at a prescribed control period(1 to 10 msec).

First, the ECU 60 calculates an operation speed (a lever operationspeed, hereinafter, may be simply referred to as a lever speed) toward aconnection side of the clutch lever 4 b (step S11). Calculation of thelever speed is performed by, for example, time differentiation of alever angle. The calculated lever operation speed is sequentially storedin the memory 62.

Next, the ECU 60 performs reading of a lever speed for control of theprevious time while calculating the current lever speed (step S12). Whenthere is no lever speed for control of the previous time, for example,immediately after starting the processing or the like, the initiallycalculated lever speed is set as a lever speed for control.

Next, the ECU 60 performs reading of the peak hold hydraulic pressurerange PH, which is previously determined, while reading the slavehydraulic pressure (step S13).

Next, the ECU 60 performs determination of whether the slave hydraulicpressure is in the peak hold hydraulic pressure range PH (step S14).

When the slave hydraulic pressure is in the peak hold hydraulic pressurerange PH (YES in step S14), the processing is shifted to step S16. Instep S16, it is determined whether the current lever speed is smallerthan a lever speed for control of the previous time.

When the current lever speed is higher than the lever speed for controlof the previous time (NO in step S16), the processing is shifted to stepS17, the current lever speed is set to the lever speed for control, andthe processing is temporarily terminated.

When the current lever speed is smaller than the lever speed for controlof the previous time (YES in step S16), the processing is shifted tostep S18, and the processing is temporarily terminated while the leverspeed for control of the previous time is set to a lever speed forcontrol.

In step S14, when the slave hydraulic pressure is outside the peak holdhydraulic pressure range PH (NO in step S14), i.e., when the slavehydraulic pressure is equal to or less than the lower limit hydraulicpressure P4 and is equal to or larger than an upper limit hydraulicpressure P3, the processing is shifted to step S15.

In step S15, the current lever speed is set to a lever speed for controland the lever speed for control of the previous time is reset, and theprocessing is temporarily terminated.

According to the processing, when the lever operation speed is high inthe peak hold hydraulic pressure range PH, the high speed side map MPHis fixed, and a higher target hydraulic pressure is set with respect tothe lever angle so that the clutch device 26 is connected more rapidly.In addition, when the peak hold control is reset, the processing returnsto the low speed side map MPL, and a way of varying a target hydraulicpressure returns to before the peak hold control. Further, while onlyone high speed side map MPH is shown in FIG. 9, a configuration in whicha plurality of high speed side maps MPH are provided and these arevaried according to a connection operation speed of the clutch lever 4 bmay be provided.

<Temporal Change of Clutch Control Parameter>

An example of a temporal change of a clutch control parameter will bedescribed with reference to FIG. 11A and FIG. 11B.

Referring to a comparative example in FIG. 11A, when a grippingoperation of the clutch lever 4 b is performed upon clutch engagement inthe automatic mode M1, a pivot angle of the clutch lever 4 b isincreased. The clutch actuator 50 is operated to be linked with anoperation (an increase in pivot angle) of the clutch lever 4 b, and atarget hydraulic pressure of clutch control (a control target value of aslave hydraulic pressure) is reduced according to variation in operationamount (pivot angle) of the clutch lever 4 b. That is, the operationtarget hydraulic pressure Pv is reduced. Accordingly, the clutch device26 is operated in a disconnection direction.

In addition, when a release operation from gripping of the clutch lever4 b is performed, a pivot angle of the clutch lever 4 b is reduced. Theclutch actuator 50 is operated to be linked with an operation (adecrease in pivot angle) of the clutch lever 4 b, and a target hydraulicpressure of clutch control (a control target value of a slave hydraulicpressure) is increased according to variation in operation amount (pivotangle) of the clutch lever 4 b. That is, the operation target hydraulicpressure Pv is increased. Accordingly, the clutch device 26 is operatedin a connection direction.

Here, the target hydraulic pressure (the operation target hydraulicpressure Pv) is controlled to vary in proportion to variation of a leverangle. In other words, the target hydraulic pressure is controlled tovary 1:1 with respect to a lever angle.

Meanwhile, a slave hydraulic pressure (and a clutch gap) that is anactual control target is varied with delay with respect to the targethydraulic pressure by an influence of a resistance (pressure loss) in ahydraulic path from the clutch actuator 50 to the slave cylinder 28.Accordingly, a slight operation delay of the clutch device 26 withrespect to an operation of the clutch lever 4 b occurs, a driver mayfeel badness of disconnection and badness of connection of the clutchdevice 26.

Referring to FIG. 11B, in the embodiment, when the target hydraulicpressure is in the peak hold hydraulic pressure range PH according tothe lever release operation speed, a target hydraulic pressure map for ahigh speed operation is selected.

Accordingly, in a region J in which a lever release operation speed ishigh, the target hydraulic pressure is varied from a target hydraulicpressure MPL′ corresponding to the low speed side map MPL, to a targethydraulic pressure MPH′ corresponding to the high speed side map MPH.Accordingly, a slave hydraulic pressure and a clutch gap can be variedearlier than the operation target hydraulic pressure Pv.

In a target hydraulic pressure map for a high speed operation, a targethydraulic pressure is increased at an earlier timing compared to atarget hydraulic pressure map for a low speed operation whichcorresponds to the operation target hydraulic pressure Pv. For thisreason, it is possible to increase a slave hydraulic pressure at anearlier timing than following the operation target hydraulic pressurePv, to reduce a clutch gap while starting a clutch stroke, and toconnect the clutch device 26.

Accordingly, even when a pressure loss in the clutch hydraulic path ispresent, a delay of an operation of the clutch device 26 can beminimized. For this reason, a time required for re-connection of theclutch can be reduced, and a driver cannot easily feel badness ofconnection of the clutch device 26 (make the driver to feel that aclutch connection follows a lever operation) upon a connectionoperation. In other words, connection responsiveness of the clutchdevice 26 can be improved.

After that, when the slave hydraulic pressure exceeds or falls below thepeak hold hydraulic pressure range PH, the peak hold control isterminated, and returns to the hydraulic pressure control based on theoperation target hydraulic pressure Pv. Accordingly, the clutch device26 can be connected linearly according to the lever operation.

Before and after the manual intervention control, a control target valueof a clutch capacity is set to an automated control target hydraulicpressure Pa separated from the manual clutch operation. Further, thepeak hold control is not limited to be performed in the manualintervention mode M3 and may be performed in the manual mode M2.

As described above, the clutch control device 60A of the embodimentincludes the clutch device 26 configured to disconnect and connect apower transmission between the engine 13 and the gearbox 21, the clutchactuator 50 configured to drive the clutch device 26 and vary a clutchcapacity, the ECU 60 configured to calculate a control target value ofthe clutch capacity, the clutch lever 4 b configured to manually operatethe clutch device 26, and the clutch lever operation amount sensor 4 cconfigured to convert an operation amount of the clutch lever 4 b intoan electrical signal. The ECU 60 calculates a clutch operation speed onthe basis of the operation amount detected by the clutch lever operationamount sensor 4 c and changes a disconnection and connection speed ofthe clutch device 26 according to the clutch operation speed.

According to the configuration, since the clutch connection speed isvaried by the lever operation speed, when the clutch operation is rapid,disconnection and connection of the clutch device 26 can be rapidlyperformed according to the operation. For this reason, disconnection andconnection performance of the clutch device 26 can be improved(responsiveness with respect to the clutch operation can be improved).

In the clutch control device 60A, the ECU 60 changes a disconnection andconnection speed of the clutch device 26 by changing a control targetvalue of the clutch capacity according to the clutch operation speed.

According to the configuration, by changing the target hydraulicpressure according to the lever operation speed, it is possible toimprove the disconnection and connection performance of the clutchdevice 26 by simply changing the control target value of the clutchcapacity and without changing the hardware.

In the clutch control device 60A, the ECU 60 disconnects and connectsthe clutch device 26 according to a control target value map (the highspeed side map MPH) corresponding to a fastest operation speed when acurrent clutch operation speed does not reach the fastest operationspeed among the clutch operation speeds stored in the memory 62.

According to the configuration, since it is fixed to a control map ofthe fastest lever operation speed during the clutch operation, even whenthe clutch operation speed is decreased in midway, disconnection andconnection of the clutch device 26 can be stably rapidly performedwithout decreasing the disconnection and connection speed of the clutchdevice 26.

In the clutch control device 60A, the ECU 60 disconnects and connectsthe clutch device 26 according to a control target value map (the highspeed side map MPH) corresponding to a fastest operation speed using thecurrent clutch operation speed as the fastest operation speed when thecurrent clutch operation speed exceeds the fastest operation speed amongthe clutch operation speeds stored in the memory 62.

According to the configuration, when the clutch operation speed isincreased in midway, since the disconnection and connection speed of theclutch device is increased according thereto, responsiveness withrespect to the clutch operation can be further improved.

In the clutch control device 60A, a control parameter sensor (thedownstream-side hydraulic pressure sensor 58) configured to detect acontrol parameter (a slave hydraulic pressure) of a clutch capacity isprovided, and the ECU 60 disconnects and connects the clutch device 26according to the control target map (the high speed side map MPH)corresponding to the fastest operation speed when the control parameterreaches the first control target value (the lower limit hydraulicpressure P4).

According to the configuration, since the processing is shifted to thepeak hold control when the control parameter of the clutch capacityreaches the first control target value, and a disconnection andconnection speed of the clutch device 26 is increased by switching thecontrol target value map, responsiveness with respect to the clutchoperation can be timely increased.

In the clutch control device 60A, the ECU 60 releases the clutch controlaccording to the control target map corresponding to the fastestoperation speed when the control parameter reaches the secondpredetermined control target value (the upper limit hydraulic pressureP3).

According to the configuration, since the peak hold control is releasedwhen the control parameter of the clutch capacity reaches the secondcontrol target value, and the control of increasing the disconnectionand connection speed of the clutch device 26 is released, energyconsumption by an operation of clutch actuator 50 after reaching theclutch connection hydraulic pressure can be minimized.

<Switching of Feedback Control>

Referring to FIG. 14 and FIG. 16, in the clutch control device 60A ofthe embodiment, when the clutch actuator 50 is feedback-controlled sothat the actual control parameter (the slave hydraulic pressure)approaches the control target value of the clutch capacity (the targethydraulic pressure), switching of a method of feedback control(proportional-integral-differential (PID) control) is performedaccording to the connection operation speed of the clutch lever 4 b.

In the above mentioned feedback control, when the same control isperformed before and after reaching the touch point hydraulic pressureTP, connection of the clutch device 26 may be delayed or a difference incontrol target value may be excessively increased. In addition, when theclutch capacity is controlled by a hydraulic pressure, since a friction(a flow resistance or a pressure loss in an oil passage) is present in ahydraulic path, a delay in variation in slave hydraulic pressure withrespect to variation in target hydraulic pressure occurs. For thisreason, occurrence of an event that the slave hydraulic pressuresubstantially reaches the touch point hydraulic pressure TP while theclutch capacity does not reach the touch point hydraulic pressure TP canbe considered.

In the embodiment, feedback control of the control parameter (the slavehydraulic pressure) is varied before and after the touch point hydraulicpressure TP. Here, as shown in FIG. 17, the touch point hydraulicpressure TP that is previously determined is varied according to theconnection operation speed of the clutch lever 4 b. Specifically, as theconnection operation speed of the clutch lever 4 b is increased, a valueobtained by adding the pressure loss with respect to the predeterminedtouch point hydraulic pressure TP is set as a determination hydraulicpressure to perform switching of control.

Referring to FIG. 14 and FIG. 16, when the feedback control is varied,in a region in which a lever angle is larger and an amount of change (arate of change) per a time of the lever angle is a predetermined levelor more (a region in which the clutch device 26 is stroked, hereinafter,referred to as a stroke region), feedback control due to an I term (anintegral term) main is performed. A measured hydraulic pressure duringthe clutch stroke (a slave hydraulic pressure) corresponds to a sum of aload of a return spring (clutch spring) reaction force and a load of apressure loss.

During the clutch stroke, even when a duty of the motor control of theclutch actuator 50 is increased, the slave hydraulic pressure is only areturn spring load+a pressure loss.

In the stroke region, since it is a half clutch, an engine rotationalnumber (NE) is increased. A motor duty and an I term start to increaseduring a second half. A clutch gap starts falling (decreasing) after anincrease in motor duty and I term. The slave hydraulic pressure iscontrolled with a basic I term because a deviation from the targethydraulic pressure is small.

Then, at a timing when the slave hydraulic pressure exceeds the touchpoint hydraulic pressure TP, the I term is reset, and shifts to thefeedback control utilizing the P term (the deviation term), the I termand the D term (the derivative term). After the touch point (afterstarting the clutch connection), since a state of the clutch device 26is largely varied with respect to before the touch point (during theclutch stroke), the feedback control is also changed according thereto,and overshoot or hunting is minimized.

Accordingly, upon a half clutch after the clutch connection is started,it is shifted to a load control region in which a transmission load iscontrolled according to a slave hydraulic pressure. After starting theclutch connection, the pressure is varied according to almost the duty.The measured hydraulic pressure in the load control region correspondsto an extent of a return spring load+a pushing load. Further, in theembodiment, since the touch point hydraulic pressure TP that is acontrol switching threshold is varied according to a connectionoperation speed of the clutch lever 4 b, even when an oil path pressureloss extent is varied according to the lever operation speed, switchingof the feedback control can be performed while having the variation ofthe loss extent being included.

Next, an example of processing performed by the ECU 60 upon switching offeedback control will be described with reference to a flowchart in FIG.15. A control flow is repeatedly performed at a prescribed controlperiod (1 to 10 msec).

First, the ECU 60 reads a detected value of the downstream-sidehydraulic pressure sensor 58 to measure a slave hydraulic pressure (stepS22) while performing feedback control using the I term main (step S21).

Next, the ECU 60 determines whether the measured slave hydraulicpressure reaches the touch point hydraulic pressure TP (step S23).

When the slave hydraulic pressure does not reach the touch pointhydraulic pressure TP (NO in step S23), the processing returns to stepS21 or is temporarily terminated.

When the slave hydraulic pressure reaches the touch point hydraulicpressure TP (YES in step S23), it is shifted to step S24, is switched toa feedback control mainly using the P term (or using each of the P term,the I term and the D term), and is temporarily terminated.

An example of a temporal change of a clutch control parameter whenfeedback control is varied will be described with reference to FIG. 16.

In the stroke region, while the lever angle is reduced, a counter shafttorque and an engine rotational number (NE) are increased in a secondhalf of the stroke region. A throttle angle (TH) is increased accordingto reduction of the lever angle (pivoting toward the clutch connectionside), and the NE starts to increase after an increase in TH. Forexample, a timing of an increase in NE with respect to an increase in THcan be controlled by a throttle-by-wire. A counter shaft torque isgradually increased while waving according to an increase in NE, and avehicle speed is eventually increased.

A clutch gap starts to decrease after a lever angle is reduced for someextent. In the stroke region in which a rate of change of the leverangle is large, while a high motor duty including also an oil pathpressure loss is required, since a deviation between the targethydraulic pressure and the slave hydraulic pressure is small in thestroke region, feedback control using the I term (integral term) main isperformed. Meanwhile, in the load control region, a hydraulic pressureovershoot and a shock torque are reduced by switching to an appropriatePID distribution.

Switching (change of a control state) between the stroke region and theload control region is conventionally performed at a switching threshold(a control state change determination value) that assumes the touchpoint hydraulic pressure TP. However, since the oil path pressure lossvalue is varied according to the clutch stroke speed, the oil pathpressure loss value is added to the switching threshold. That is, forexample, when the clutch device 26 is rapidly connected by a rapid leveroperation, the oil path pressure loss value is increased and theswitching threshold is increased (see FIG. 17).

When energy is lost by a viscous resistance of a fluid, the pressure islost from an upstream side toward a downstream side of pressurization.For this reason, a pressure actually applied to the slave cylinder 28 issmaller than a value of the downstream-side hydraulic pressure sensor 58separated at an upstream side while the clutch device 26 is stroked andthe fluid flows. Accordingly, a pressure loss extent should be added toa detection value of the downstream-side hydraulic pressure sensor 58.In addition, the pressure loss extent is increased as a clutch operationspeed is increased.

For this reason, the switching threshold is set based on a table usingthe lever operation speed shown in FIG. 17. That is, while the touchpoint hydraulic pressure TP is statically equivalent to a return springload of the clutch device 26, when the lever operation is rapid, a loadof the increased oil path pressure loss extent is added. Accordingly, ahydraulic pressure value to which an oil path pressure loss extent isadded is set to the switching threshold according to an increase inlever operation speed.

In the stroke region, feedback control of the I term main is performed.In the load control region, since the lever operation speed isdecreased, the oil path pressure loss is reduced, and linear hydraulicpressure characteristics are obtained with respect to the duty.Accordingly, in the load control region, the processing is switched tothe feedback control using the P term, the I term and the D term.

When the control state is changed across the touch point hydraulicpressure TP, determination of whether the integral term is rest isperformed using a determination value (a switching threshold) accordingto the lever operation speed. Accordingly, it is possible to obtain aclutch connection feeling having linearity with respect to the leveroperation for each conditions in which an operation speed of the clutchlever 4 b to the connection side differs with each other.

As described above, the clutch control device 60A of the embodimentperforms feedback control (PID control) such that the ECU 60 sets acontrol target value of a clutch capacity according to an operationamount detected by the clutch lever operation amount sensor 4 c andcauses a control parameter detected by the control parameter sensor (thedownstream-side hydraulic pressure sensor 58) to approach the controltarget value, and changes a method of the feedback control when thecontrol parameter reaches a predetermined control state changedetermination value (the touch point hydraulic pressure TP) during thefeedback control.

According to the configuration, since the method of the feedback controlis changed when the control parameter of the clutch capacity reaches thecontrol state change determination value, for example, controls whichare appropriate for the stroke region before reaching the control statechange determination value and for the load control region afterreaching the control state change determination value can be performed.For this reason, it is possible to improve connection performance of theclutch device 26 by quickening the convergence of the control parameter.In addition, since the control state change determination value is seton the basis of the clutch operation amount, for example, even when theoil path pressure loss extent of the clutch operation system isaffected, connection performance of the clutch device 26 can be improvedsimilarly.

In the clutch control device 60A, the ECU 60 performs the feedbackcontrol on the basis of the I term in the PID control before the controlparameter reaches the control state change determination value, andperforms the feedback control on the basis of the P term in the PIDcontrol after the control parameter reaches the control state changedetermination value.

According to the configuration, since weighting of each terms of the PIDcontrol of the clutch actuator 50 is varied before and after the controlparameter of the clutch capacity reaches the control state changedetermination value (before and after the slave hydraulic pressurereaches the touch point hydraulic pressure TP), appropriate feedbackcontrol can be performed. Specifically, the feedback control can beperformed using the I term (integral term) main before the controlparameter reaches the control state change determination value, and thefeedback control can be performed using the P term (deviation term) mainafter the control parameter reaches the control state changedetermination value. For this reason, the convergence of the controlparameter can be accelerated in the load control region in a later stageof the clutch operation while quickening a clutch stroke in the strokeregion at the beginning of the clutch operation.

In the clutch control device 60A, the clutch device 26 switches whetherto perform the power transmission or not to perform the powertransmission when the control parameter reaches the control state changedetermination value. That is, the clutch device 26 is switched between aconnection state in which power transmission is possible and adisconnection state in which power transmission is not possible when thecontrol parameter reaches the control state change determination value.

According to the configuration, since the method of the feedback controlis changed at a touch point at which it is switched whether to performthe power transmission or not to perform the power transmission of theclutch device 26 (i.e., switched between a connection state in whichpower transmission is possible and a disconnection state in which powertransmission is not possible), the feedback control can be changedaccording to the state variation of the clutch device 26, and it ispossible to accelerate the convergence of the control parameter whilesuppressing overshoot or hunting of the control parameter.

In the clutch control device 60A, the ECU 60 calculates a clutchoperation speed on the basis of an operation amount detected by theclutch lever operation amount sensor 4 c, and varies the control statechange determination value according to the clutch operation speed.

According to the configuration, since the control state changedetermination value is varied depending on the clutch operation speed(the lever operation speed), for example, even when the oil pathpressure loss extent of the clutch operation system is affected, it ispossible to vary the control state change determination value whileconsidering the loss extent. For this reason, it is possible toaccurately change the feedback control at the touch point at which it isswitched whether the clutch device 26 performs the power transmission ornot to perform the power transmission (i.e., switched between aconnection state in which power transmission is possible and adisconnection state in which power transmission is not possible).

In the clutch control device 60A, the clutch capacity is controlled bythe hydraulic pressure, the master cylinder 51 of the clutch actuator 50and the slave cylinder 28 of the clutch device 26 are connected to eachother via the hydraulic pressure pipeline, and the control parametersensor (the downstream-side hydraulic pressure sensor 58) that is theslave hydraulic pressure sensor is disposed in the hydraulic pressurepipeline.

According to the configuration, it is possible to increase a degree ofdisposition freedom of the slave hydraulic pressure sensor, and evenwhen the slave hydraulic pressure sensor and the slave cylinder 28 aredisposed at places separated from each other, it is possible toaccurately control the clutch capacity.

Further, the present invention is not limited to the embodiment, and forexample, may be applied to a configuration in which the clutch isdisconnected with an increase in hydraulic pressure and the clutch isconnected with a decrease in hydraulic pressure without being limited toan application to a configuration in which the clutch is connected withan increase in hydraulic pressure and the clutch is disconnected with adecrease in hydraulic pressure.

The clutch operator is not limited to the clutch lever and may be aclutch pedal or other various operators.

The present invention is not limited to a saddle riding vehicle in whicha clutch operation is automated like the embodiment and may also beapplied to a saddle riding vehicle including a so-called clutchoperationless transmission configured to adjust a driving force andshift gears without performing a manual clutch operation under apredetermined condition while setting the manual clutch operation as abasic operation.

In addition, all vehicles on which a driver rides on the vehicle bodyare included as the saddle riding vehicle, and in addition to amotorcycle (including a motorized bicycle and a scooter-type vehicle), athree-wheeled vehicle (including a two-front-wheeled andone-rear-wheeled vehicle in addition to one-front-wheeled andtwo-rear-wheeled vehicle) or a four-wheeled vehicle may also beincluded, and a vehicle in which an electric motor is included in aprime mover may also be included.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the scope of the present invention. Accordingly, theinvention is not to be considered as being limited by the foregoingdescription, and is only limited by the scope of the appended claims.

What is claimed is:
 1. A clutch control device comprising: an engine; a gearbox; a clutch device that disconnects and connects a power transmission between the engine and the gearbox; a clutch actuator that drives the clutch device and changes a clutch capacity; a controller that calculates a control target value of the clutch capacity; a control parameter sensor that detects a control parameter of the clutch capacity; a clutch operator that manually operates the clutch device; and a clutch operation amount sensor that converts an operation amount of the clutch operator into an electrical signal, wherein the controller sets a control target value of the clutch capacity according to the operation amount detected by the clutch operation amount sensor, executes feedback control so that the control parameter which is detected by the control parameter sensor approaches the control target value, and changes a method of the feedback control when the control parameter reaches a predetermined control state change determination value during the feedback control.
 2. The clutch control device according to claim 1, wherein the controller performs the feedback control on the basis of an I term in a PID control before the control parameter reaches the control state change determination value, and performs the feedback control on the basis of a P term in the PID control after the control parameter reaches the control state change determination value.
 3. The clutch control device according to claim 1, the clutch device switches whether to perform the power transmission or not to perform the power transmission when the control parameter reaches the control state change determination value.
 4. The clutch control device according to claim 1, wherein the controller calculates a clutch operation speed on the basis of an operation amount detected by the clutch lever operation amount sensor, and varies the control state change determination value according to the clutch operation speed.
 5. The clutch control device according to claim 1, wherein the clutch capacity is controlled by the hydraulic pressure, a master cylinder of the clutch actuator and a slave cylinder of the clutch device are connected to each other via a hydraulic pressure pipeline, and the control parameter sensor that is a slave hydraulic pressure sensor is disposed in the hydraulic pressure pipeline.
 6. The clutch control device according to claim 5, wherein when the hydraulic pressure decreases the clutch capacity decreases and the clutch device is disconnected.
 7. The clutch control device according to claim 1, wherein the clutch operator is a clutch lever, and the clutch operation amount sensor detects a pivot angle of the clutch lever. 